package com.jdaw.datastructure.huffmantree;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;


public class HuffManTree {
    public static void main(String[] args) {
        int arr[]={13, 7, 8, 3, 29, 6, 1};
        Node root=createHuffmanTree(arr);
        preOrder(root);
    }

    public static void preOrder(Node root){
        if(root!=null){
            root.preOrder();
        }else{
            System.out.println("该树为空");
        }
    }

    public static Node createHuffmanTree(int[] arr){
        List<Node> nodes=new ArrayList<Node>();
        for(int value:arr){
            nodes.add(new Node(value));
        }

        while(nodes.size()>1){
            Collections.sort(nodes);
            //取出权值第一第二小的节点
            Node leftNode=nodes.get(0);
            Node rightNode=nodes.get(1);
            Node parent=new Node(leftNode.value+rightNode.value);
            parent.left=leftNode;
            parent.right=rightNode;
            nodes.remove(leftNode);
            nodes.remove(rightNode);
            nodes.add(parent);
        }
        return nodes.get(0);

    }
}

class Node implements Comparable<Node>{
    int value;
    Node left;
    Node right;

    public Node(int value) {
        this.value = value;
    }

    //写一个前序遍历
    public void preOrder(){
        System.out.println(this);
        if(this.left!=null){
            this.left.preOrder();
        }
        if(this.right!=null){
            this.right.preOrder();
        }
    }

    @Override
    public String toString() {
        return "Node{" +
                "value=" + value +
                '}';
    }

    //重写是为了之后排序时比较
    @Override
    public int compareTo(Node o) {
        //表示从小到大排序
        return this.value-o.value;
    }
}